Building proteomic pathways using Drosophila ventral furrow formation as a model

Area of Science:

• Developmental Biology
• Cell Biology
• Proteomics

Background:

• Ventral furrow formation is the initial morphogenetic event in Drosophila gastrulation, involving mesodermal precursor internalization.
• A prior proteomic screen identified ~40 ventral-specific "difference-proteins" with diverse cellular functions.

Purpose of the Study:

• To elucidate the connections between disparate proteins involved in ventral furrow formation.
• To investigate the role of the proteasomal subunit Pros35 in this process and identify associated regulatory pathways.

Main Methods:

• Pathway-building using cycles of protein expression manipulation and proteome analysis.
• RNA interference (RNAi) to alter Pros35 levels and subsequent proteome analysis.
• Analysis of Transferrin (Tsf1) and iron regulatory protein Irp-1A roles in ventral furrow formation.

Main Results:

• Altering Pros35 levels caused ventral furrow defects, with proteome changes overlapping the original ventral-specific difference-proteins.
• Pros35 RNAi negated the ventral-specific difference in Transferrin (Tsf1) abundance.
• Increased Tsf1 in wild-type embryos blocked ventral furrow formation and induced proteome changes similar to ventral-specific difference-proteins.

Conclusions:

• A novel regulatory loop exists between the proteasome and iron homeostasis, involving Pros35, Tsf1, and Irp-1A.
• This loop coordinates a significant number of ventral-specific protein changes during Drosophila gastrulation.
• Pros35 is identified as a key regulator in ventral furrow formation and embryonic development.